group of individuals of the same species, occupying the same time and space, with the potential of interbreeding
Species:
group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding successfully
Evolution by Natural Selection:
organisms with heritable traits that favor survival and reproduction will tend to leave more offspring than their peers, causing the traits to increase in frequency over generations
Brown et al. 2007: 6 genetically distinct lineages of giraffe
Evolution by Natural Selection: Darwin and others
A few things need to be true…
Individuals in a population are not identical
Some variation among individuals in heritable
Individuals sometimes die before reproducing
Different ancestors leave different #’s of descendants
How did giraffes get long necks? (Lamarck vs Darwin)
What is Generational Time? Why does it matter?
Species are so specialized, they are absent almost everywhere
How many species of bees do you think there are in the USA?
Diversity of living things evolves over long time periods
Why does this matter for Ecology?
Survival of the fittest is tied to organisms interacting with their environment
This term is a little misleading, should read:
Survival of the better designed for an immediate, local environment
survived death
reproduced successfully
The components and themes of ecology matters a lot!
environment is hardly ever stable
Ecological forces drive evolution
Some traits of plants and animals are ‘conserved’
not easily modified
However,we often seem lots of variation within a species
Species traits vary over geographic ranges
why?
’Ohi’a lehua tree on Hawaiian Islands
Intra-specific variation can occur at short distances
Evolution also driven by species interactions
Selection forces: pressures on an trait by natural selection driving evolution of a population
Steam guppies in Trinidad are separated by waterfalls
isolated populations
tons of different traits across guppy populations
What selection forces could be driving these changes?
Predation, sex and flamboyance in guppies
Great tit (Parus major) and bird feeders (Bosse et al. 2017)